Interspecies features of hepatic cytochromes P450 IA1 and P450 IA2 in rodents.
1. Antibodies to mouse liver cytochrome P3-450 (anti-P3-450) and antibodies to rat liver cytochrome P-450d (anti-P-450d-c) both inhibit the O-deethylation of 7-ethoxy-resorufin (ER) in liver microsomes of benzo(a)pyrene-induced (BP) mice but do not inhibit the O-deethylase activity in liver microsomes of BP-induced rats. 2. Anti-P3-450 and anti-P-450d-c inhibit BP hydroxylation in BP-induced mouse liver microsomes by 20%, but they do not inhibit this rection at all in BP-induced rat liver microsomes. 3. Isolated cytochrome P3-450 in a reconstituted monooxygenase system metabolized 7-ER and BP. In contrast, its homologue, cytochrome P-450d, does not metabolize these substrates. The fraction containing cytochrome P1-450 metabolized 7-ER at a low rate and BP at a rate of 3.6 nmol product/min per nmol cytochrome. 4. Western blot analysis with anti-P-450c + d revealed two bands in SDS-PAGE gels containing BP-induced mouse liver microsomes corresponding to cytochrome P1-450, 55.0 kDa, and cytochrome P3-450, 54.5 kDa. There appeared a single band (cytochrome P3-450) in interaction of mouse liver BP-microsomes with anti-P3-450 and anti-P-450d-c.
Tsyrlov
I B
IB
Institute of Clinical and Experimental Medicine, Academy of Medical Sciences, Novosibirsk, USSR.
Duzchak
T G
TG
D000818:Animals; D001564:Benzo(a)pyrene / Q000494:pharmacology; D019388:Cytochrome P-450 CYP1A2; D065607:Cytochrome P-450 Enzyme Inhibitors; D003577:Cytochrome P-450 Enzyme System / Q000276:immunology / Q000302:isolation & purification*; D003580:Cytochromes / Q000302:isolation & purification*; D007120:Immunochemistry; D008099:Liver / Q000201:enzymology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008862:Microsomes, Liver / Q000187:drug effects / Q000201:enzymology; D010088:Oxidoreductases / Q000037:antagonists & inhibitors / Q000276:immunology / Q000302:isolation & purification*; D051381:Rats; D011919:Rats, Inbred Strains; D013045:Species Specificity; D013379:Substrate Specificity
D065607:Cytochrome P-450 Enzyme Inhibitors; D003580:Cytochromes; D001564:Benzo(a)pyrene; D003577:Cytochrome P-450 Enzyme System; D010088:Oxidoreductases; D019388:Cytochrome P-450 CYP1A2